U.S. patent number 5,773,399 [Application Number 08/648,111] was granted by the patent office on 1998-06-30 for stabilization of oxidation-sensitive ingredients in percarbonate detergent compositions.
This patent grant is currently assigned to The Procter & Gamble Comapny. Invention is credited to Gerard Marcel Baillely, Richard Timothy Hartshorn.
United States Patent |
5,773,399 |
Baillely , et al. |
June 30, 1998 |
Stabilization of oxidation-sensitive ingredients in percarbonate
detergent compositions
Abstract
Granular laundry detergents are formulated with percarbonate
bleach and oxidation-sensitive ingredients such as brighteners,
enzymes, perfumes and the like. The storage stability of such
compositions is improved by the presence of silicate. For example,
the tendency of stilbene-type brighteners to form undesirable
yellow shades in the presence of percarbonate is diminished by the
corporation of silicate materials into the granules.
Inventors: |
Baillely; Gerard Marcel
(Newcastle upon Tyne, GB3), Hartshorn; Richard
Timothy (Newcastle upon Tyne, GB3) |
Assignee: |
The Procter & Gamble
Comapny (Cincinnati, OH)
|
Family
ID: |
26134596 |
Appl.
No.: |
08/648,111 |
Filed: |
May 21, 1996 |
PCT
Filed: |
December 01, 1994 |
PCT No.: |
PCT/US94/13653 |
371
Date: |
May 21, 1996 |
102(e)
Date: |
May 21, 1996 |
PCT
Pub. No.: |
WO95/16019 |
PCT
Pub. Date: |
June 15, 1995 |
Foreign Application Priority Data
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|
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Dec 10, 1993 [EP] |
|
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93309960 |
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Current U.S.
Class: |
510/315; 510/307;
510/309; 510/317; 510/349; 510/375; 510/377; 510/438; 510/441 |
Current CPC
Class: |
C11D
3/046 (20130101); C11D 3/08 (20130101); C11D
3/10 (20130101); C11D 3/1233 (20130101); C11D
3/128 (20130101); C11D 3/386 (20130101); C11D
3/3917 (20130101); C11D 3/42 (20130101); C11D
3/50 (20130101); C11D 17/06 (20130101) |
Current International
Class: |
C11D
3/386 (20060101); C11D 3/12 (20060101); C11D
3/08 (20060101); C11D 3/50 (20060101); C11D
3/38 (20060101); C11D 3/02 (20060101); C11D
17/06 (20060101); C11D 3/39 (20060101); C11D
3/40 (20060101); C11D 3/42 (20060101); C11D
003/08 (); C11D 003/395 () |
Field of
Search: |
;510/307,309,315,317,324,375,377,446,466,349,438,441 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0 518 576 A2 |
|
Dec 1992 |
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EP |
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2122044 |
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Jan 1984 |
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GB |
|
Primary Examiner: Lieberman; Paul
Assistant Examiner: Dusheck; Caroline L.
Attorney, Agent or Firm: Patel; Ken K. Zerby; Kim W. Rasser;
Jacobus C.
Claims
What is claimed is:
1. A granular composition comprising from 0.04% to about 15% by
weight of oxidation-sensitive ingredients in combination with a
detergent composition, the detergent composition comprising:
(a) from 10% to 85% by weight of the detergent composition of
particles which comprise, by weight of the particles (a):
(i) from 5% to 80% of a builder which is selected from the group
consisting of zeolite builders, carbonate builders, and mixtures
thereof;
(ii) from about 2% to about 15% of a silicate;
(iii) from 5% to 60% of a detersive surfactant, or mixtures of
detersive surfactants;
(iv) from 0% to 70% of a water-soluble sulfate salt, said sulfate
salt being contaminated with no more than 60 ppm iron and no more
than 5 ppm copper; and
(v) when said water-soluble sulfate salt is present at a level of
1% or greater in said particle, from 0.3% to 15% of a chelant;
(b) from 3% to 50% by weight of the detergent composition of
percarbonate bleach particles having an average particle size in
the range from 500 micrometers to 1000 micrometers, not more than
10% by weight of said percarbonate particles being smaller than 200
micrometers and not more than 10% by weight of said percarbonate
particles being larger than 1250 micrometers, wherein said
percarbonate particles optionally include a coating, and further
wherein the coating, if included, consists of water-soluble
carbonates, water-soluble sulfates, water-soluble citrates,
dehydrated or partially hydrated zeolites, water-soluble
surfactants, or mixtures thereof;
(c) from 12% to 35% by weight of the detergent composition of
particles consisting essentially of water-soluble sulfate, said
sulfate particles being dry-blended with particles (a) and (b),
said sulfate particles being contaminated with no more than 40 ppm
iron and no more than 5 ppm copper, said sulfate particles having
an average particle size in the range from 250 micrometers to 1400
micrometers, not more than 25% by weight of said sulfate particles
being larger than 1000 micrometers and not more than 2% of said
sulfate particles being smaller than 250 micrometers; and
(d) optionally, adjunct ingredients;
wherein the oxidation-sensitive ingredients comprise optical
brighteners, perfumes, enzymes, fabric softeners, or mixtures
thereof.
2. A composition according to claim 1 wherein particle (a) has a
moisture content not exceeding 13% by weight.
3. A composition according to claim 2 wherein particle (a) has a
moisture content of at least 2%, by weight.
4. A composition according to claim 1 wherein particle (a)
comprises a builder selected from the group consisting of zeolites
A, P, MAP, X, Y and mixtures thereof, sodium carbonate builders,
and mixtures thereof.
5. A composition according to claim 1 wherein percarbonate
particles (b) have a moisture content not greater than 1% by weight
of said percarbonate particles.
6. A composition according to claim 1 wherein the particles of
sulfate (c) contain less than 25 ppm iron.
7. A composition according to claim 1 wherein the moisture content
of the overall composition is not greater than 8% by weight.
8. A composition according to claim 1 wherein the optical
brightener is
4,4'-bis[4-anilino-6-morpholino-1,3,5-triazin-2-yl)amino]-stilbene-2,2'-di
sulfonate.
9. A composition according to claim 1 wherein said silicate is
sodium silicate.
10. A composition according to claim 2 wherein particle (a) has a
moisture content of less than 10% by weight.
11. A composition according to claim 5 wherein said percarbonate
bleach particles (b) have a moisture content not greater than 0.5%
by weight of said percarbonate particles.
12. A composition according to claim 6 wherein the particles of
sulfate (c) contain less than 5 ppm iron.
13. A composition according to claim 12 wherein the particles of
sulfate (c) have an average particle size in the range of 450
micrometers to 800 micrometers.
14. A composition according to claim 1 wherein the optical
brightener comprises a stilbene, pyrazoline, coumarin, carboxylic
acid, a methinecyanine, dibenzothiphene-5,5-dioxide, an azole, or a
5- or 6-membered-ring heterocycle.
15. A composition according to claim 1 wherein the chelant
comprises an amino carboxylate, amino phosphonate,
polyfunctionally-substituted aromatic chelating agent, or mixture
thereof.
16. A composition according to claim 1 wherein the particles of
sulfate (c) consist essentially of sodium sulfate, magnesium
sulfate or aluminum sulfate.
17. A composition according to claim 1 wherein the particles of
sulfate (c) comprise from about 12% to about 25%, by weight, of the
detergent composition.
Description
TECHNICAL FIELD
The present invention relates to granular detergent compositions
which contain a percarbonate bleach and one or more
oxidation-sensitive ingredients such as fluorescent whitening
agents, enzymes, perfumes, chelants, and the like. The compositions
are formulated not only to provide good detergency and bleaching
performance, but also to diminish or eliminate the oxidation of
such ingredients during storage of the compositions.
BACKGROUND OF THE INVENTION
The formulation of modem granular laundry detergents without the
use of phosphate builders and under various constraints with
respect to fabric safety and environmental effects is a substantial
challenge. The formulator is faced with the need to provide
detergent compositions which remove a wide variety of soils and
stains from a wide variety of fabrics. Detergent compositions must
function effectively over a wide range of wash temperatures. They
must be storage-stable over a wide range of temperatures and
humidities. Granular detergents should desirably be free-flowing
and easily dispensed in automatic equipment. They must not suds too
much nor too little. To be affordable, they must be formulated
using economical, yet safe and effective, ingredients. Accordingly,
there continues to be a substantial investment in the search for
new and improved detergent compositions.
Inorganic bleaches such as percarbonate offer prospective
advantages to the detergent formulator due to their inherent
cleaning ability. Moreover, percarbonate bleaches offer prospective
advantages over the commonly-used perborate bleach, inasmuch as
they do not disadvantageously interact with important new
surfactants such as the polyhydroxy fatty acid amides. In addition,
there is now some indication that perborate bleach can sometimes
undesirably complex with, and stabilize, "polyol" stains, such as
the polyphenolic materials found in chocolate. Percarbonates do not
suffer from this disadvantage. Moreover, if properly formulated,
especially as disclosed herein, percarbonate can provide superior
dispensing properties as compared with perborate.
Another type of ingredient which is often incorporated into
granular laundry detergents comprises the fluorescent whitening
agents, more commonly referred to as "brighteners" or "optical
bleaches". Such agents do not, themselves, provide a true
"bleaching" and stain removal function, as does percarbonate.
Rather, such agents are designed to deposit onto fabrics,
especially white fabrics, to subtly adjust the overall visual
perception from an undesirable "yellowish" shade to a "bluish"
shade, which the consumer perceives as an improvement in the
whiteness and brightness of the laundered fabric.
Unfortunately, it has now been found that granular detergents which
contain the desirable percarbonate bleach can undesirably cause
yellowing of certain oxidation-sensitive optical brighteners. It
has now further been discovered that this undesirable yellowing
effect is especially problematic with the commercially important
class of stilbene brighteners.
Yet another type of ingredient which is often used in granular
laundry detergents comprises the various classes of detersive
enzymes, including proteases, amylases, lipases, cellulases and
mixtures thereof. It has now been determined that such enzymes can
be wholly or partly inactivated in percarbonate-containing
detergent compositions. Likewise, it has now further been
discovered that other oxidation-sensitive detergent ingredients
such as perfumes, unsaturated organics such as oleic acid, oleate
soaps and oleyl sulfate, fatty amine fabric softeners and
surfactants, amino chelants, and the like, are all susceptible to
oxidative degradation on storage in the presence of percarbonate
bleach.
While not intending to be limited by theory, it may now be
hypothesized that, even with so-called "stabilized" percarbonate,
there is always some leakage of H.sub.2 O.sub.2 from the
percarbonate into the balance of the product on storage. This
peroxide leakage is exacerbated at the higher storage temperatures
and relative humidities which may be experienced in warehouses.
Moreover, it has now been determined that if the presence of metal
ions, e.g., copper and iron, is minimized, the "leaked" H.sub.2
O.sub.2 may be relatively harmless to oxidation-sensitive
ingredients. However, if uncontrolled metal ions are present, they
appear to catalytically decompose the leaked H.sub.2 O.sub.2 into
oxygen radicals which can decompose any oxidation-sensitive
ingredients.
By the present invention, it has been discovered that the inclusion
of certain silicate materials into percarbonate-containing laundry
granules prepared as disclosed herein minimizes the aforesaid
degradation problems.
BACKGROUND ART
The use of brighteners for various purposes, including their use in
laundry detergents, is discussed in Encyclopedia of Chemical
Technology, Kirk-Othmer, Vol. 4, 3rd Ed., pages 213-226, John Wiley
& Sons 1978. Problems associated with stability are noted at
pages 222-223. EP 451,893; U.S. Pat. No. 5,236,613; Japanese
A-4-227,693; Japanese 63-62442 and Japanese KOKOKU 61-16319 relate
to percarbonate bleach. Detersive enzymes and/or enzyme stabilizers
are described in U.S. Pat. Nos. 4,261,868, 3,600,619, 3,519,570 and
European 0,199,405.
SUMMARY OF THE INVENTION
The present invention encompasses the use of a silicate material
(especially water-soluble silicate but also magnesium silicate
colloids) to diminish or eliminate the oxidative degradation of
oxidation-sensitive ingredients in granular detergent compositions,
especially laundry detergents, which contain a percarbonate bleach.
Such oxidation-sensitive ingredients include optical brighteners,
perfumes, enzymes, chelants, fabric softeners, various unsaturated
materials, and mixtures thereof, examples of which are disclosed
hereinafter or are known to detergent formulators.
In a preferred mode the finished granular compositions afforded by
this invention comprise from 0.04% to about 15% by weight of one or
more of the aforesaid oxidation-sensitive ingredients in
combination with a detergent composition, characterized in that
said detergent composition comprises:
(a) from 10% to 85% by weight of composition particles which
comprise:
(i) from 5% to 80% by weight of particle of a builder which is a
member selected from the group consisting of zeolite builders,
carbonate builders, or mixtures thereof;
(ii) from about 2% to about 15% by weight of a silicate, most
preferably a sodium silicate;
(iii) from 5% to 60% by weight of particle of a detersive
surfactant, or mixtures of detersive surfactants;
(iv) from 0% to 70% by weight of particle of a water-soluble
inorganic sulfate salt, said sulfate salt being contaminated with
no more than 60 ppm iron and no more than 5 ppm copper;
(v) when said water-soluble sulfate salt is present at a level of
1% or greater in said particle, from 0.3% to 15% by weight of a
chelant;
(b) from 3% to 50% by weight of composition of percarbonate bleach
particles having an average particle size in the range from 500
micrometers to 1000 micrometers, not more than 10% by weight of
said percarbonate being particles smaller than 200 micrometers and
not more than 10% by weight of said particles being larger than
1250 micrometers;
(c) from 0% to 35% by weight of composition of water-soluble
sulfate particles, said particles being dry-blended with particles
(a) and (b), said sulfate particles being contaminated with no more
than 40 ppm ion and no more than 5 ppm copper, said sulfate
particles having an average particle size in the range from 250
micrometers to 1400 micrometers, not more than 25% by weight of
said sulfate particles being larger than 1000 micrometers and not
more than 2% of said particles being smaller than 250 micrometers;
and
(d) optional adjunct ingredients.
In order to achieve optimal overall product stability, particle (a)
should have a moisture content not exceeding 13%, most preferably
less than 10%, by weight. In order to achieve good flowability and
dispensing in automatic equipment, particle (a) should have a
moisture content of at least 2%, by weight. If particle (a) is
prepared by spray-drying, it preferably should have a moisture
content of at least about 7%, by weight.
Preferred compositions herein are those wherein particle (a)
comprises a builder selected from the group consisting of zeolites
A, P, MAP, X, Y or mixtures thereof, sodium carbonate builders, and
mixtures thereof.
When particle (a) also comprises greater than 1% of an optional
water-soluble sulfate component, it typically will also contain a
chelant, preferably selected from the group consisting of
phosphonate, amino carboxylate, and polycarboxylate chelants, and
mixtures thereof, usually at levels of from 0.3% to 4.0% by weight
in said particle.
For stability on storage, the particles of percarbonate bleach (b)
may be coated, e.g., with a member selected from the group
consisting of water-soluble carbonate, water-soluble sulfate,
water-soluble citrate, dehydrated or partially hydrated zeolite,
water-soluble surfactants, or mixtures thereof. Whether or not
stabilized by such means, the particles of percarbonate bleach
preferably have an average size in the range from 500 micrometers
to 1,000 micrometers. For stability purposes, it is also preferred
that percarbonate particles (b) have a moisture content not greater
than 1%, more preferably not greater than 0.5%, by weight of said
percarbonate particles.
When the product also contains dry blended sulfate, it is preferred
in order to provide further stability to the percarbonate that the
particles of sulfate (c) contain less than 25 ppm, preferably less
than 5 ppm, iron, and preferably have an average particle size in
the range of 450 micrometers to 800 micrometers.
In a preferred mode, the moisture content of the overall
compositions herein is not greater than 8% by weight.
All percentages, ratios and proportions herein are by weight,
unless otherwise specified. All documents cited are incorporated
herein by reference.
DETAILED DESCRIPTION OF THE INVENTION
The following describes the brightener component and typical
formulations and formulation components used herein, but is not
limiting thereof.
Percarbonate Bleach--The percarbonate bleach employed herein is the
conventional percarbonate material available from suppliers such as
Solvay, FMC, Tokai Denka and others. If desired, and to provide
additional stability on storage, the particles of percarbonate can
be coated or "dusted" with various materials such as sodium
citrate, sodium carbonate, sodium sulfate, water-soluble
surfactants, and mixtures thereof. Thus, a stabilized percarbonate
bleach can comprise 2.5% of a 2.5:1 sodium carbonate:sodium sulfate
by weight, or can comprise 5% citrate. A preferred percarbonate
bleach is in the form of particles having an average particle size
in the range from 500 micrometers to 1,000 micrometers, not more
than 10% by weight of said percarbonate being particles smaller
than 200 micrometers and not more than 10% by weight of said
particles being larger than 1,200 micrometers. Typical compositions
will comprise from about 50% to about 25% by weight of percarbonate
bleach.
Silicate--The silicate stabilizer used herein especially includes
the alkali metal silicates having an SiO.sub.2 :Na.sub.2 O ratio
("R") in the range of from about 1.6:1 to 3.2:1, although silicates
outside this preferred range may be useful, albeit sub-optimal. The
sodium form of the silicate is typically used, although the
inclusion of magnesium can further enhance stability of the overall
compositions, as disclosed more fully hereinafter. It is also
suitable to form in situ the Mg silicate form by adding in the same
particle (for instance, in the same slurry when preparing spray
dried particles) the sodium silicate and a magnesium salt
(magnesium sulfate or magnesium chloride, for instance). Suitable
silicates for use herein include sodium silicate 1.6 R solution,
sodium silicate 2.0 R solids or sodium silicate 3.2 R solids,
available from Hoechst or Akzo. The ratio of
silicate:oxidation-sensitive ingredient being stabilized is at
least 1:1.
Brightener--Any optical brighteners known in the art which do not
contain copper or iron species can advantageously be incorporated
into the detergent compositions herein at levels typically from
about 0.04% to about 1.2%, by weight. Commercial optical
brighteners which may be useful in the present invention can be
classified into subgroups which include, but are not necessarily
limited to, derivatives of stilbene, pyrazoline, coumarin,
carboxylic acid, methinecyanines, dibenzothiphene-5,5-dioxide,
azoles, 5- and 6-membered-ring heterocycles, and other
miscellaneous agents. Examples of such brighteners are disclosed in
"The Production and Application of Fluorescent Brightening Agents",
M. Zahradnik, Published by John Wiley & Sons, New York
(1982).
Specific examples of optical brighteners can be used in the present
compositions are those identified in U.S. Pat. No. 4,790,856,
issued to Wixon on Dec. 13, 1988. These brighteners include the
PHORWHITE series of brighteners from Verona. Other brighteners
disclosed in this reference include: Tinopal UNPA, Tinopal CBS and
Tinopal 5BM; available from Ciba-Geigy; Arctic White CC and Artic
White CWD, available from Hilton-Davis, located in Italy; the
2-(4-styryl-phenyl)-2H- naphthol[1,2-d]triazoles; 4,4'-bis-
(1,2,3-triazol-2-yl)-stilbenes; 4,4'-bis(styryl)bisphenyls; and the
aminocoumarins. Specific examples of these brighteners include
4-methyl-7-diethyl- amino coumarin;
1,2-bis(-benzimidazol-2-yl)ethylene; 1,3-diphenylphrazolines;
2,5-bis(benzoxazol-2-yl)thiophene; 2-styryl-naphth-[1,2-d]oxazole;
and 2-(stilbene-4-yl)-2H-naphtho-[1,2-d]triazole. See also U.S.
Pat. No. 3,646,015, issued Feb. 29, 1972 to Hamilton.
It is to be understood that, while the present invention can be
used with all the aforesaid classes of brighteners and mixtures
thereof, it is of special importance for use with stilbene-type
brighteners, due to their tendency to yellow in the presence of
percarbonate bleach. The invention is especially useful with
disodium
4,4'-bis[(4-anilino-6-morpholino-1,3,5-triazin-2yl)amino]stilbene2,2'-disu
lfonate available from Ciba-Geigy as Tinopal DMS and disodium
4,4'-bis(4,6-di-anilino-1,3,5-triazin-2-yl)amino stilbene 2
disulfonate brighteners.
Enzymes--Enzymes can be included in the formulations herein for a
wide variety of fabric laundering purposes, including removal of
protein-based, carbohydrate-based, or triglyceride-based stains,
for example, and for the prevention of refugee dye transfer, and
for fabric restoration. The enzymes to be incorporated include
proteases, amylases, lipases, cellulases, and peroxidases, as well
as mixtures thereof. Other types of enzymes may also be included.
They may be of any suitable origin, such as vegetable, animal,
bacterial, fungal and yeast origin. However, their choice is
governed by several factors such as pH-activity and/or stability
optima, thermostability, stability versus active detergents,
builders and so on. In this respect bacterial or fungal enzymes are
preferred, such as bacterial amylases and proteases, and fungal
cellulases.
Enzymes are normally incorporated at levels sufficient to provide
up to about 5 mg by weight, more typically about 0.01 mg to about 3
mg, of active enzyme per gram of the composition. Stated otherwise,
the compositions herein will typically comprise from about 0.001%
to about 5%, preferably 0.01%-1%, by weight of a commercial enzyme
preparation. Protease enzymes are usually present in such
commercial preparations at levels sufficient to provide from 0.005
to 0.1 Anson units (AU) of activity per gram of composition.
Suitable examples of proteases are the subtilisins which are
obtained from particular strains of B.subtilis and B.licheniforms.
Another suitable protease is obtained from a strain of Bacillus,
having maximum activity throughout the pH range of 8-12, developed
and sold by Novo Industries A/S under the registered trade name
ESPERASE. The preparation of this enzyme and analogous enzymes is
described in British Patent Specification No. 1,243,784 of Novo.
Proteolytic enzymes suitable for removing protein-based stains that
are commercially available include those sold under the tradenames
ALCALASE and SAVINASE by Novo Industries A/S (Denmark) and MAXATASE
by International Bio-Synthetics, Inc. (The Netherlands). Other
proteases include Protease A (see European Patent Application
130,756, published Jan. 9, 1985) and Protease B (see European
Patent Application Serial No. 87303761.8, filed Apr. 28, 1987, and
European Patent Application 130,756, Bott et al, published Jan. 9,
1985).
Amylases include, for example, a-amylases described in British
Patent Specification No. 1,296,839 (Novo), RAPIDASE, International
Bio-Synthetics, Inc. and TERMAMYL, Novo Industries.
The cellulases usable in the present invention include both
bacterial or fungal cellulase. Preferably, they will have a pH
optimum of between 5 and 9.5. Suitable cellulases are disclosed in
U.S. Pat. No. 4,435,307, Barbesgoard et al, issued Mar. 6, 1984,
which discloses fungal cellulase produced from Humicola insolens
and Humicola strain DSM1800 or a cellulase 212-producing fungus
belonging to the genus Aeromonas, and cellulase extracted from the
hepatopancreas of a marine mollusk (Dolabella Auricula Solander).
Suitable cellulases are also disclosed in GB-A-2.075.028;
GB-A-2.095.275 and DE-OS-2.247.832.
Suitable lipase enzymes for detergent usage include those produced
by microorganisms of the Pseudomonas group, such as Pseudomonas
stutzeri ATCC 19.154, as disclosed in British Patent 1,372,034. See
also lipases in Japanese Patent Application 53-20487, laid open to
public inspection on Feb. 24, 1978. This lipase is available from
Amano Pharmaceutical Co. Ltd., Nagoya, Japan, under the trade name
Lipase P "Amano," hereinafter referred to as "Amano-P." Other
commercial lipases include Amano-CES, lipases ex Chromobacter
viscosum, e.g. Chromobacter viscosum var. lipolyticum NRRLB 3673,
commercially available from Toyo Jozo Co., Tagata, Japan; and
further Chromobacter viscosum lipases from U.S. Biochemical Corp.,
U.S.A. and Disoynth Co., The Netherlands, and lipases ex
Pseudomonas gladioli. The LIPOLASE enzyme derived from Humicola
lanuginosa and commercially available from Novo (see also EPO
341,947) is a preferred lipase for use herein.
Peroxidase enzymes are used in combination with oxygen sources,
e.g., percarbonate, perborate, persulfate, hydrogen peroxide, etc.
They are used for "solution bleaching," i.e. to prevent transfer of
dyes or pigments removed from substrates during wash operations to
other substrates in the wash solution. Peroxidase enzymes are known
in the art, and include, for example, horseradish peroxidase,
ligninase, and haloperoxidase such as chloro- and bromo-peroxidase.
Peroxidase-containing detergent compositions are disclosed, for
example, in PCT International Application WO 89/099813, published
Oct. 19, 1989, by O. Kirk, assigned to Novo Industries A/S.
A wide range of enzyme materials and means for their incorporation
into synthetic detergent granules are also disclosed in U.S. Pat.
No. 3,553,139, issued Jan. 5, 1971 to McCarty et al. Enzymes are
further disclosed in U.S. Pat. No. 4,101,457, Place et al, issued
Jul. 18, 1978, and in U.S. Pat. No. 4,507,219, Hughes, issued Mar.
26, 1985, both. Enzyme materials useful for detergent formulations
are also disclosed in U.S. Pat. No. 4,261,868, Hora et al, issued
Apr. 14, 1981. The stability of SAVINASE, ENDO GLUCANASE A,
cellulases, amylases and lipases are all enhanced by the practice
of the present invention.
Chelating Agents--The detergent compositions herein may also
optionally contain one or more iron and/or manganese chelating
agents, especially when a sulfate salt is present. Typically, the
overall compositions may comprise from about 0.1% to about 10% by
weight of such chelants. Such chelating agents can be selected from
the group consisting of amino carboxylates, amino phosphonates,
polyfunctionally-substituted aromatic chelating agents and mixtures
thereof, all as hereinafter defined. Without intending to be bound
by theory, it is believed that the benefit of these materials is
due in part to their exceptional ability to remove iron and
manganese ions from washing solutions by formation of soluble
chelates.
Amino carboxylates useful as optional chelating agents include
ethylene-diaminetetraacetates,
N-hydroxyethylethylenediaminetriacetates, nitrilotriacetates,
ethylenediamine tetraproprionates,
triethylenetetraaminehexaacetates, diethylenetriaminepentaacetates,
and ethanoldiglycines, alkali metal, ammonium, and substituted
ammonium salts therein and mixtures therein.
Amino phosphonates are also suitable for use as chelating agents in
the compositions of the invention when at least low levels of total
phosphorus are permitted in detergent compositions, and include
ethylenediaminetetrakis (methylenephosphonates), nitrilotris
(methylenephosphonates) and diethylenetriaminepentakis
(methylenephosphonates) as DEQUEST ("DTPMP"). Preferably, these
amino phosphonates do not contain alkyl or alkenyl groups with more
than about 6 carbon atoms. HEDP, 1,hydroxyethane diphosphonate, is
suitable and preferably combined with aminophosphonates or amino
carboxylates for use herein.
Polyfunctionally-substituted aromatic chelating agents are also
useful in the compositions herein. See U.S. Pat. No. 3,812,044,
issued May 21, 1974, to Connor et al. Preferred compounds of this
type in acid form are dihydroxydisulfobenzenes such as
1,2-dihydroxy -3,5-disulfobenzene.
A preferred biodegradable chelator for use herein is
ethylenediamine disuccinate ("EDDS"), especially the [S,S] form, as
described in U.S. Pat. No. 4,704,233, Nov. 3, 1987, to Hartman and
Perkins.
Perfumes--With respect to perfume stability, the compositions
herein exhibit improved stability with respect to perfume
ingredients that are sensitive to oxidation, especially aldehydes
and ketones. Thus, perfumery ingredients such as the floral scents,
the woody scents, the citrus scents and the musk scents, and blends
thereof, all of which comprise varying amounts of aldehyde and
ketone components, are advantageously employed herein. Importantly,
the common perfume "carriers" such as the phthalates, especially
diethyl phthalate, are also stable in the present compositions.
Perfumery ingredients and/or carriers typically comprise from 0.01%
to 2% of the present compositions.
Additional Formulation Components
The following describes the formulation ingredients used in
addition to those above-disclosed.
Detergency Builders--The compositions also contain various
conventional builders, or, optionally, mixtures of builders,
typically at levels from about 5% to about 60%, by weight. Such
builders assist in controlling mineral hardness in wash liquors and
to assist in the removal of particulate soils from fabrics.
Aluminosilicate (zeolite) builders are quite useful in particles
(a) herein and such builders are of great importance in most
currently marketed heavy duty granular detergent compositions.
Aluminosilicate builders include those having the empirical
formula:
wherein M is sodium, potassium, ammonium or substituted ammonium, z
is from about 0.5 to about 2; and y is 1; this material having a
magnesium ion exchange capacity of at least about 50 milligram
equivalents of CaCO.sub.3 hardness per gram of anhydrous
aluminosilicate. Preferred aluminosilicates are zeolite builders
which have the formula:
wherein z and y are integers of at least 6, the molar ratio of z to
y is in the range from 1.0 to about 0.5, and x is an integer from
about 15 to about 264.
Useful aluminosilicate ion exchange materials are commercially
available. These aluminosilicates can be crystalline or amorphous
in structure and can be naturally-occurring aluminosilicates or
synthetically derived. A method for producing aluminosilicate ion
exchange materials is disclosed in U.S. Pat. No. 3,985,669,
Krummel, et al, issued Oct. 12, 1976. Preferred synthetic
crystalline aluminosilicate ion exchange materials useful herein
are available under the designations Zeolite A, Zeolite P (B),
Zeolite X, Zeolite Y, and Zeolite MAP. In an especially preferred
embodiment, the crystalline aluminosilicate ion exchange material
has the formula:
wherein x is from about 20 to about 30, especially about 27. This
material is known as Zeolite A. Dehydrated (x=0-10) Zeolite A can
also be used. Preferably, the aluminosilicate has a particle size
of about 0.1-10 microns in diameter. Mixtures of zeolites with
organic builders such as citrate are also useful.
Examples of other silicate builders useful herein include the
layered sodium silicates described in U.S. Pat. No. 4,664,839,
issued May 12, 1987 to H. P. Rieck. NaSKS-6 is the trademark for a
crystalline layered silicate marketed by Hoechst (commonly
abbreviated herein as "SKS-6"). Unlike zeolite builders, the Na
SKS-6 silicate builder does not contain aluminum. NaSKS-6 has the
delta-Na.sub.2 SiO.sub.5 morphology form of layered silicate. It
can be prepared by methods such as those described in German
DE-A-3,417,649 and DE-A-3,742,043. SKS6 is a highly preferred
layered silicate for use herein, but other such layered silicates,
such as those having the general formula NaMSi.sub.x O.sub.2x+1
yH.sub.2 O wherein M is sodium or hydrogen, x is a number from 1.9
to 4, preferably 2, and y is a number from 0 to 20, preferably 0
can be used herein. Various other layered silicates from Hoechst
include NaSKS-5, NaSKS-7 and NaSKS-11, as the alpha, beta and gamma
forms. As noted above, the delta-Na.sub.2 SiO.sub.5 (NaSKS-6 form)
is most preferred for use herein. Other silicates may also be
useful such as for example magnesium silicate, which can serve as a
crispening agent in granular formulations, as a stabilizing agent
for oxygen bleaches, and as a component of suds control systems.
Mixtures of silicates, especially layered silicates, with organic
builders such as citrate are also useful.
Examples of carbonate builders are the alkaline earth and alkali
metal carbonates as disclosed in German Patent Application No.
2,321,001 published on Nov. 15, 1973. Typical examples include
calcite and sodium carbonate.
In addition to the foregoing zeolite, silicate or carbonate
builders, the finished compositions herein can optionally also
comprise from 2% to 20% of various organic detergent builders,
including, but not restricted to, a wide variety of polycarboxylate
compounds. Such builders can be dry-mixed with the overall
compositions, or, less preferably, can be incorporated into
particle (a). As used herein, "polycarboxylate" refers to compounds
having a plurality of carboxylate groups, preferably at least 3
carboxylates. Polycarboxylate builder can generally be added to the
composition in acid form, but can also be added in the form of a
neutralized salt. When utilized in salt form, alkali metals, such
as sodium, potassium, and lithium, or alkanolammonium salts are
preferred.
Included among the polycarboxylate builders are a variety of
categories of useful materials. One important category of
polycarboxylate builders encompasses the ether polycarboxylates,
including oxydisuccinate, as disclosed in Berg, U.S. Pat. No.
3,128,287, issued Apr. 7, 1964, and Lamberti et al, U.S. Pat. No.
3,635,830, issued Jan. 18, 1972. See also "TMS/TDS" builders of
U.S. Pat. No. 4,663,071, issued to Bush et al, on May 5, 1987.
Suitable ether polycarboxylates also include cyclic compounds,
particularly alicyclic compounds, such as those described in U.S.
Pat. Nos. 3,923,679; 3,835,163; 4,158,635; 4,120,874 and
4,102,903.
Other useful detergency builders include the ether
hydroxypolycarboxylates, copolymers of maleic anhydride with
ethylene or vinyl methyl ether, 1, 3,5-trihydroxy benzene-2, 4,
6-trisulphonic acid, and carboxymethyloxysuccinic acid, the various
alkali metal, ammonium and substituted ammonium salts of polyacetic
acids such as ethylenediamine tetraacetic acid and nitrilotriacetic
acid, as well as polycarboxylates such as mellitic acid, succinic
acid, oxydisuccinic acid, polymaleic acid, benzene
1,3,5-tricarboxylic acid, carboxymethyloxysuccinic acid, and
soluble salts thereof.
Citrate builders, e.g., citric acid and soluble salts thereof
(particularly sodium salt), are polycarboxylate builders of
particular importance due to their availability from renewable
resources and their biodegradability. Citrates are often used in
granular compositions in combination with zeolite and/or layered
silicate builders. Oxydisuccinates are also useful in such
compositions and combinations.
Also suitable in the detergent compositions of the present
invention are the 3,3-dicarboxy-4-oxa-1,6-hexanedioates and the
related compounds disclosed in U.S. Pat. No. 4,566,984, Bush,
issued Jan. 28, 1986. Useful succinic acid builders include the
C.sub.5 -C.sub.20 alkyl and alkenyl succinic acids and salts
thereof. A particularly preferred compound of this type is
dodecenylsuccinic acid. Specific examples of succinate builders
include: laurylsuccinate, myristylsuccinate, palmitylsuccinate,
2-dodecenylsuccinate (preferred), 2-pentadecenylsuccinate, and the
like. Laurylsuccinates are the preferred builders of this group,
and are described in European Patent Application
86200690.5/0,200,263, published Nov. 5, 1986.
Other suitable polycarboxylates are disclosed in U.S. Pat. No.
4,144,226, Crutchfield et al, issued Mar. 13, 1979 and in U.S. Pat.
No. 3,308,067, Diehl, issued Mar. 7, 1967. See also Diehl U.S. Pat.
No. 3,723,322.
Fatty acids, e.g., C.sub.12 -C.sub.18 monocarboxylic acids, can
also be incorporated into the compositions alone, or in combination
with the aforesaid builders, especially citrate and/or the
succinate builders, to provide additional builder activity. Such
use of fatty acids will generally result in a diminution of
sudsing, which should be taken into account by the formulator.
While not preferred, in those situations where phosphorus-based
builders can be used, the various alkali metal phosphates such as
the well-known sodium tripolyphosphates, sodium pyrophosphate and
sodium orthophosphate can be used.
Detersive Surfactants--The compositions herein also contain various
anionic surfactants, or, optionally, mixtures of anionics with
nonionic, zwitterionic or semipolar surfactants, typically at
levels from about 5% to about 40%, by weight.
Nonlimiting examples of surfactants useful herein include the
conventional C.sub.11 -C.sub.18 alkyl benzene sulfonates ("LAS")
and primary, branched-chain and random C.sub.10 -C.sub.20 alkyl
sulfates ("AS"), the C.sub.10 -C.sub.18 secondary (2,3) alkyl
sulfates of the formula CH.sub.3 (CH.sub.2).sub.x
(CHOSO.sub.3.sup.- M.sup.+)CH.sub.3 and CH.sub.3 (CH.sub.2).sub.y
(CHOSO.sub.3.sup.- M.sup.+) CH.sub.2 CH.sub.3 where x and (y+1) are
integers of at least about 7, preferably at least about 9, and M is
a water-solubilizing cation, especially sodium, the C.sub.10
-C.sub.18 alkyl alkoxy sulfates ("AE.sub.x S"; especially EO 1-5
ethoxy sulfates), C.sub.10 -C.sub.18 alkyl alkoxy carboxylates
(especially the EO 1-5 ethoxycarboxylates), the C.sub.10-18
glycerol ethers, the C.sub.10 -C.sub.18 alkyl polyglycosides and
their corresponding sulfated polyglycosides, and C.sub.12 -C.sub.18
alpha-sulfonated fatty acid esters. If desired, the conventional
nonionic and amphoteric surfactants such as the C.sub.12 -C.sub.18
alkyl ethoxylates ("AE") including the so-called narrow peaked
alkyl ethoxylates and C.sub.6 -C.sub.12 alkyl phenol alkoxylates
(especially ethoxylates and mixed ethoxy/propoxy), C.sub.12
-C.sub.18 betaines and sulfobetaines ("sultaines"), C.sub.10
-C.sub.18 amine oxides, and the like, can also be included in the
overall compositions. The C.sub.10 -C.sub.18 N-alkyl polyhydroxy
fatty acid amides can also be used. Typical examples include the
C.sub.12 -C.sub.18 N-methylglucamides. Other conventional useful
surfactants are listed in standard texts.
Sulfate Salts--The compositions herein most preferably comprise a
water-soluble inorganic sulfate salt having the physical and
chemical parameters disclosed hereinabove. Typical examples of such
salts include sodium sulfate, magnesium sulfate and aluminum
sulfate. The compositions typically comprise from about 12% to
about 25%, by weight, of sulfate.
Adjunct Ingredients
The compositions herein can optionally include one or more other
detergent adjunct materials or other materials for assisting or
enhancing cleaning performance, treatment of the substrate to be
cleaned, or to modify the aesthetics of the detergent composition
(e.g., perfumes, colorants, dyes, etc.). The following are
illustrative, but nonlimiting, examples of such materials.
Enzyme Stabilizers--The enzymes employed herein can be further
stabilized by the presence of water-soluble sources of calcium
and/or magnesium ions in the finished compositions which provide
such ions to the enzymes. Additional stability can be provided by
the presence of various other art-disclosed stabilizers, especially
borate species: see Severson, U.S. Pat. No. 4,537,706, cited above.
Typical detergents will comprise from about 1 to about 30,
preferably from about 2 to about 20, more preferably from about 5
to about 15, and most preferably from about 8 to about 12,
millimoles of calcium ion per kilo of finished composition. This
can vary somewhat, depending on the amount of enzyme present and
its response to the calcium or magnesium ions. The level of calcium
or magnesium ions should be selected so that there is always some
minimum level available for the enzyme, after allowing for
complexation with builders, fatty acids, etc., in the composition.
Any water-soluble calcium or magnesium salt can be used as the
source of calcium or magnesium ions, including, but not limited to,
calcium chloride, calcium sulfate, calcium malate, calcium maleate,
calcium hydroxide, calcium formate, and calcium acetate, and the
corresponding magnesium salts. A small amount of calcium ion,
generally from about 0.05 to about 0.4 millimoles per kilo, is
often also present in the composition due to calcium in the enzyme
slurry and formula water. In granular detergent compositions the
formulation may include a sufficient quantity of a water-soluble
calcium ion source to provide such amounts in the laundry liquor.
In the alternative, natural water hardness may suffice.
It is to be understood that the foregoing levels of calcium and/or
magnesium ions are sufficient to provide enzyme stability. More
calcium and/or magnesium ions can be added to the compositions to
provide an additional measure of grease removal performance.
Accordingly, the compositions herein may comprise from about 0.05%
to about 2% by weight of a water-soluble source of calcium or
magnesium ions, or both. The amount can vary, of course, with the
amount and type of enzyme employed in the composition.
The compositions herein may also optionally, but preferably,
contain various additional stabilizers, especially borate-type
stabilizers. Typically, such stabilizers will be used at levels in
the compositions from about 0.25% to about 10%, preferably from
about 0.5% to about 5%, more preferably from about 0.75% to about
3%, by weight of boric acid or other borate compound capable of
forming boric acid in the composition (calculated on the basis of
boric acid). Boric acid is preferred, although other compounds such
as boric oxide, borax and other alkali metal borates (e.g., sodium
ortho-, meta- and pyroborate, and sodium pentaborate) are suitable.
Substituted boric acids (e.g., phenylboronic acid, butane boronic
acid, and p-bromo phenylboronic acid) can also be used in place of
boric acid.
Bleach Activators--The detergent compositions herein may optionally
contain bleaching agents or bleaching compositions containing a
bleaching agent and one or more bleach activators. If present, the
amount of bleach activators will typically be from about 0.1% to
about 60%, more typically from about 0.5% to about 40% of the
bleaching composition comprising the percarbonate bleaching
agent-plus-bleach activator.
The percarbonates are preferably used in the presence of bleach
activators, which lead to the in situ production in aqueous
solution (i.e., during the washing process) of the peroxy acid
corresponding to the bleach activator. Various nonlimiting examples
of activators are disclosed in U.S. Pat. No. 4,915,854, issued Apr.
10, 1990 to Mao et al, and U.S. Pat. No. 4,412,934. The
nonanoyloxybenzene sulfonate (NOBS) and tetraacetyl ethylene
diamine (TAED) activators are typical, and mixtures thereof can
also be used. Benzoyl caprolactam and benzoyloxybenzene sulfonate
activators can also be used. See also U.S. Pat. No. 4,634,551 for
other typical bleaches and activators useful herein.
Bleaching agents other than percarbonate bleaching agents are known
in the art and can optionally also be utilized herein. One type of
non-oxygen bleaching agent of particular interest includes
photoactivated bleaching agents such as the sulfonated zinc and/or
aluminum phthalocyanines. See U.S. Pat. No. 4,033,718, issued Jul.
5, 1977 to Holcombe et al. If used, detergent compositions will
typically contain from about 0.025% to about 1.25%, by weight, of
such photoactivated bleaches, especially sulfonated zinc
phthalocyanine.
Polymeric Soil Release Agent--Any polymeric soil release agent
known to those skilled in the art can optionally be employed in the
compositions and processes of this invention. Polymeric soil
release agents are characterized by having both hydrophilic
segments, to hydrophilize the surface of hydrophobic fibers, such
as polyester and nylon, and hydrophobic segments, to deposit upon
hydrophobic fibers and remain adhered thereto through completion of
washing and rinsing cycles and, thus, serve as an anchor for the
hydrophilic segments. This can enable stains occurring subsequent
to treatment with the soil release agent to be more easily cleaned
in later washing procedures.
The polymeric soil release agents useful herein especially include
those soil release agents having: (a) one or more nonionic
hydrophile components consisting essentially of (i) polyoxyethylene
segments with a degree of polymerization of at least 2, or (ii)
oxypropylene or polyoxypropylene segments with a degree of
polymerization of from 2 to 10, wherein said hydrophile segment
does not encompass any oxypropylene unit unless it is bonded to
adjacent moieties at each end by ether linkages, or (iii) a mixture
of oxyalkylene units comprising oxyethylene and from 1 to about 30
oxypropylene units wherein said mixture contains a sufficient
amount of oxyethylene units such that the hydrophile component has
hydrophilicity great enough to increase the hydrophilicity of
conventional polyester synthetic fiber surfaces upon deposit of the
soil release agent on such surface, said hydrophile segments
preferably comprising at least about 25% oxyethylene units and more
preferably, especially for such components having about 20 to 30
oxypropylene units, at least about 50% oxyethylene units; or (b)
one or more hydrophobe components comprising (i) C.sub.3
oxyalkylene terephthalate segments, wherein, if said hydrophobe
components also comprise oxyethylene terephthalate, the ratio of
oxyethylene terephthalate:C.sub.3 oxyalkylene terephthalate units
is about 2:1 or lower, (ii) C.sub.4 -C.sub.6 alkylene or oxy
C.sub.4 -C.sub.6 alkylene segments, or mixtures therein, (iii) poly
(vinyl ester) segments, preferably poly(vinyl acetate), having a
degree of polymerization of at least 2, or (iv) C.sub.1 -C.sub.4
alkyl ether or C.sub.4 hydroxyalkyl ether substituents, or mixtures
therein, wherein said substituents are present in the form of
C.sub.1 -C.sub.4 alkyl ether or C.sub.4 hydroxyalkyl ether
cellulose derivatives, or mixtures therein, and such cellulose
derivatives are amphiphilic, whereby they have a sufficient level
of C.sub.1 -C.sub.4 alkyl ether and/or C.sub.4 hydroxyalkyl ether
units to deposit upon conventional polyester synthetic fiber
surfaces and retain a sufficient level of hydroxyls, once adhered
to such conventional synthetic fiber surface, to increase fiber
surface hydrophilicity, or a combination of (a) and (b).
Typically, the polyoxyethylene segments of (a)(i) will have a
degree of polymerization of from 2 to about 200, although higher
levels can be used, preferably from 3 to about 150, more preferably
from 6 to about 100. Suitable oxy C.sub.4 -C.sub.6 alkylene
hydrophobe segments include, but are not limited to, end-caps of
polymeric soil release agents such as MO.sub.3 S(CH.sub.2).sub.n
OCH.sub.2 CH.sub.2 O--, where M is sodium and n is an integer from
4-6, as disclosed in U.S. Pat. No. 4,721,580, issued Jan. 26, 1988
to Gosselink.
Polymeric soil release agents useful in the present invention also
include cellulosic derivatives such as hydroxyether cellulosic
polymers, copolymeric blocks of ethylene terephthalate or propylene
terephthalate with polyethylene oxide or polypropylene oxide
terephthalate, and the like. Such agents are commercially available
and include hydroxyethers of cellulose such as METHOCEL (Dow).
Cellulosic soil release agents for use herein also include those
selected from the group consisting of C.sub.1 -C.sub.4 alkyl and
C.sub.4 hydroxyalkyl cellulose; see U.S. Pat. No. 4,000,093, issued
Dec. 28, 1976 to Nicol, et al.
Soil release agents characterized by poly(vinyl ester) hydrophobe
segments include graft copolymers of poly(vinyl ester), e.g.,
C.sub.1 -C.sub.6 vinyl esters, preferably poly(vinyl acetate)
grafted onto polyalkylene oxide backbones, such as polyethylene
oxide backbones. See European Patent Application 0 219 048,
published Apr. 22, 1987 by Kud, et al. Commercially available soil
release agents of this kind include the SOKALAN type of material,
e.g., SOKALAN HP-22, available from BASF (West Germany).
One type of soil release agent is a copolymer having random blocks
of ethylene terephthalate and polyethylene oxide (PEO)
terephthalate. The molecular weight of this polymeric soil release
agent is in the range of from about 25,000 to about 55,000. See
U.S. Pat. No. 3,959,230 to Hays, issued May 25, 1976 and U.S. Pat.
No. 3,893,929 to Basadur issued Jul. 8, 1975.
Another polymeric soil release agent is a polyester with repeat
units of ethylene terephthalate units containing 10-15% by weight
of ethylene terephthalate units together with 90-80% by weight of
polyoxyethylene terephthalate units, derived from a polyoxyethylene
glycol of average molecular weight 300-5,000. Examples of this
polymer include the commercially available material ZELCON 5126
(from Dupont) and MILEASE T (from ICI). See also U.S. Pat. No.
4,702,857, issued Oct. 27, 1987 to Gosselink.
Another polymeric soil release agent is a sulfonated product of a
substantially linear ester oligomer comprised of an oligomeric
ester backbone of terephthaloyl and oxyalkyleneoxy repeat units and
terminal moieties covalently attached to the backbone. These soil
release agents are described fully in U.S. Pat. No. 4,968,451,
issued Nov. 6, 1990 to J. J. Scheibel and E. P. Gosselink.
Other suitable polymeric soil release agents include the
terephthalate polyesters of U.S. Pat. No. 4,711,730, issued Dec. 8,
1987 to Gosselink et al, the anionic end-capped oligomeric esters
of U.S. Pat. No. 4,721,580, issued Jan. 26, 1988 to Gosselink, and
the block polyester oligomeric compounds of U.S. Pat. No.
4,702,857, issued Oct. 27, 1987 to Gosselink.
Still other polymeric soil release agents also include the soil
release agents of U.S. Pat. No. 4,877,896, issued Oct. 31, 1989 to
Maldonado et al, which discloses anionic, especially sulfoaroyl,
end-capped terephthalate esters.
If utilized, soil release agents will generally comprise from about
0.01% to about 10.0%, by weight, of the detergent compositions
herein, typically from about 0.1% to about 5%, preferably from
about 0.2% to about 3.0%.
Clay Soil Removal/Antiredeposition Agents--The compositions of the
present invention can also optionally contain water-soluble
ethoxylated amines having clay soil removal and antiredeposition
properties. Granular detergent compositions which contain such
agents typically contain from about 0.01% to about 10.0% by weight
of the water-soluble ethoxylated amines.
The most preferred clay soil removal and anti-redeposition agent is
ethoxylated tetraethylenepentamine. Exemplary ethoxylated amines
are further described in U.S. Pat. No. 4,597,898, VanderMeer,
issued Jul. 1, 1986. Another group of preferred clay soil
removal/antiredeposition agents are the cationic compounds
disclosed in European Patent Application 111,965, Oh and Gosselink,
published Jun. 27, 1984. Other clay soil removal/antiredeposition
agents which can be used include the ethoxylated amine polymers
disclosed in European Patent Application 111,984, Gosselink,
published Jun. 27, 1984; the zwitterionic polymers disclosed in
European Patent Application 112,592, Gosselink, published Jul. 4,
1984; and the amine oxides disclosed in U.S. Pat. No. 4,548,744,
Connor, issued Oct. 22, 1985. Other clay soil removal and/or anti
redeposition agents known in the art can also be utilized in the
compositions herein. Another type of preferred antiredeposition
agent includes the carboxy methyl cellulose (CMC) materials. These
materials are well known in the art.
Polymeric Dispersing Agents--Polymeric dispersing agents can
advantageously be utilized at levels from about 0.1% to about 7%,
by weight, in the compositions herein, especially in the presence
of zeolite and/or layered silicate builders. Suitable polymeric
dispersing agents include polymeric polycarboxylates and
polyethylene glycols, although others known in the art can also be
used. It is believed, though it is not intended to be limited by
theory, that polymeric dispersing agents enhance overall detergent
builder performance when used in combination with other builders
(including lower molecular weight polycarboxylates) by crystal
growth inhibition, particulate soil release peptization, and
anti-redeposition.
Polymeric polycarboxylate materials can be prepared by polymerizing
or copolymerizing suitable unsaturated monomers, preferably in
their acid form. Unsaturated monomeric acids that can be
polymerized to form suitable polymeric polycarboxylates include
acrylic acid, maleic acid (or maleic anhydride), fumaric acid,
itaconic acid, aconitic acid, mesaconic acid, citraconic acid and
methylenemalonic acid. The presence in the polymeric
polycarboxylates herein of monomeric segments, containing no
carboxylate radicals such as vinylmethyl ether, styrene, ethylene,
etc. is suitable provided that such segments do not constitute more
than about 40% by weight.
Particularly suitable polymeric polycarboxylates can be derived
from acrylic acid. Such acrylic acid-based polymers which are
useful herein are the water-soluble salts of polymerized acrylic
acid. The average molecular weight of such polymers in the acid
form preferably ranges from about 2,000 to 10,000, more preferably
from about 4,000 to 7,000 and most preferably from about 4,000 to
5,000. Water-soluble salts of such acrylic acid polymers can
include, for example, the alkali metal, ammonium and substituted
ammonium salts. Soluble polymers of this type are known materials.
Use of polyacrylates of this type in detergent compositions has
been disclosed, for example, in Diehl, U.S. Pat. No. 3,308,067,
issued Mar. 7, 1967.
Acrylic/maleic-based copolymers may also be used as a preferred
component of the dispersing/antiredeposition agent. Such materials
include the water-soluble salts of copolymers of acrylic acid and
maleic acid. The average molecular weight of such copolymers in the
acid form preferably ranges from about 2,000 to 100,000, more
preferably from about 5,000 to 75,000, most preferably from about
7,000 to 70,000. The ratio of acrylate to maleate segments in such
copolymers will generally range from about 30:1 to about 1:1, more
preferably from about 10:1 to 2:1. Water-soluble salts of such
acrylic acid/maleic acid copolymers can include, for example, the
alkali metal, ammonium and substituted ammonium salts. Soluble
acrylate/maleate copolymers of this type are known materials which
are described in European Patent Application No. 66915, published
Dec. 15, 1982.
Another polymeric material which can be included is polyethylene
glycol (PEG). PEG can exhibit dispersing agent performance as well
as act as a clay soil removal/antiredeposition agent. Typical
molecular weight ranges for these purposes range from about 500 to
about 100,000, preferably from about 1,000 to about 50,000, more
preferably from about 1,500 to about 10,000.
Polyaspartate and polyglutamate dispersing agents (mol. wt. about
10,000) may also be used, especially in conjunction with zeolite
builders.
It is to be understood that, while the present invention can be
used with all the aforesaid classes of brighteners and mixtures
thereof, it is of special importance for use with stilbene-type
brighteners, especially distilbene brighteners, due to their
tendency to yellow in the presence of percarbonate.
Suds Suppressors--Compounds for reducing or suppressing the
formation of suds can be incorporated into the compositions of the
present invention. Suds suppression can be of particular importance
under conditions such as those found in European-style front
loading laundry washing machines, or in the concentrated detergency
process of U.S. Pat. Nos. 4,489,455 and 4,489,574, or when the
detergent compositions herein optionally include a relatively high
sudsing adjunct surfactant.
A wide variety of materials may be used as suds suppressors, and
suds suppressors are well known to those skilled in the art. See,
for example, Kirk Othmer Encyclopedia of Chemical Technology, Third
Edition, Volume 7, pages 430-447 (John Wiley & Sons, Inc.,
1979). One category of suds suppressor of particular interest
encompasses monocarboxylic fatty acids and soluble salts therein.
See U.S. Pat. No. 2,954,347, issued Sep. 27, 1960 to Wayne St.
John. The monocarboxylic fatty acids and salts thereof used as suds
suppressor typically have hydrocarbyl chains of 10 to about 24
carbon atoms, preferably 12 to 18 carbon atoms. Suitable salts
include the alkali metal salts such as sodium potassium, and
lithium salts, and ammonium and alkanolammonium salts.
The detergent compositions herein may also contain non-surfactant
suds suppressors. These include, for example: high molecular weight
hydrocarbons such as paraffin, fatty acid esters (e.g., fatty acid
triglycerides), fatty acid esters of monovalent alcohols, aliphatic
C.sub.18 -C.sub.40 ketones (e.g. stearone), etc. Other suds
inhibitors include N-alkylated amino triazines such as tri- to
hexa-alkylmelamines or di- to tetra-alkyldiamine chlortriazines
formed as products of cyanuric chloride with two or three moles of
a primary or secondary amine containing 1 to 24 carbon atoms,
propylene oxide, and monostearyl phosphates such as monostearyl
alcohol phosphate ester and monostearyl di-alkali metal (e.g. K,
Na, and Li) phosphates and phosphate esters. The hydrocarbons such
as paraffin and haloparaffin can be utilized in liquid form. The
liquid hydrocarbons will be liquid at room temperature and
atmospheric pressure, and will have a pour point in the range of
about -40.degree. C. and about 5.degree. C., and a minimum boiling
point not less than about 110.degree. C. (atmospheric pressure). It
is also known to utilize waxy hydrocarbons, preferably having a
melting point below about 100.degree. C. The hydrocarbons
constitute a preferred category of suds suppressor for detergent
compositions. Hydrocarbon suds suppressors are described, for
example, in U.S. Pat. No. 4,265,779, issued May 5, 1981 to Gandolfo
et al. The hydrocarbons, thus, include aliphatic, alicyclic,
aromatic, and heterocyclic saturated or unsaturated hydrocarbons
having from about 12 to about 70 carbon atoms. The term "paraffin,"
as used in this suds suppressor discussion, is intended to include
mixtures of true paraffins and cyclic hydrocarbons.
Another preferred category of non-surfactant suds suppressors
comprises silicone suds suppressors. This category includes the use
of polyorganosiloxane oils, such as polydimethylsiloxane,
dispersions or emulsions of polyorganosiloxane oils or resins, and
combinations of polyorganosiloxane with silica particles wherein
the polyorganosiloxane is chemisorbed of fused onto the silica.
Silicone suds suppressors are well known in the art and are, for
example, disclosed in U.S. Pat. No. 4,265,779, issued May 5, 1981
to Gandolfo et al and European Patent Application No. 89307851.9,
published Feb. 7, 1990, by Starch, M. S.
Other silicone suds suppressors are disclosed in U.S. Pat. No.
3,455,839 which relates to compositions and processes for defoaming
aqueous solutions by incorporating therein small amounts of
polydimethylsiloxane fluids.
Mixtures of silicone and silanated silica are described, for
instance, in German Patent Application DOS 2,124,526. Silicone
defoamers and suds controlling agents in granular detergent
compositions are disclosed in U.S. Pat. No. 3,933,672, Bartolotta
et al, and in U.S. Pat. No. 4,652,392, Baginski et al, issued Mar.
24, 1987.
An exemplary silicone based suds suppressor for use herein is a
suds suppressing amount of a suds controlling agent consisting
essentially of:
(i) polydimethylsiloxane fluid having a viscosity of from about 20
cs. to about 1500 cs. at 25.degree. C.;
(ii) from about 5 to about 50 parts per 100 parts by weight of (i)
of siloxane resin composed of (CH.sub.3).sub.3 SiO.sub.1/2 units of
SiO.sub.2 units in a ratio of from (CH.sub.3).sub.3 SiO.sub.1/2
units and to SiO.sub.2 units of from about 0.6:1 to about 1.2:1;
and
(iii) from about 1 to about 20 parts per 100 parts by weight of (i)
of a solid silica gel.
In the preferred silicone suds suppressor used herein, the solvent
for a continuous phase is made up of certain polyethylene glycols
or polyethylene-polypropylene glycol copolymers or mixtures thereof
(preferred), and not polypropylene glycol. The primary silicone
suds suppressor is branched/crosslinked and not linear.
To illustrate this point further, typical laundry detergent
compositions with controlled suds will optionally comprise from
about 0.001 to about 1, preferably from about 0.01 to about 0.7,
most preferably from abut 0.05 to about 0.5, weight % of said
silicone suds suppressor, which comprises (1) a nonaqueous emulsion
of a primary antifoam agent which is a mixture of (a) a
polyorganosiloxane, (b) a resinous siloxane or a silicone
resin-producing silicone compound, (c) a finely divided filler
material, and (d) a catalyst to promote the reaction of mixture
components (a), (b) and (c), to form silanolates; (2) at least one
nonionic silicone surfactant; and (3) polyethylene glycol or a
copolymer of polyethylene-polypropylene glycol having a solubility
in water at room temperature of more than about 2 weight %; and
without polypropylene glycol. Similar amounts can be used in
granular compositions, gels, etc. See also U.S. Pat. No. 4,978,471,
Starch, issued Dec. 18, 1990, and U.S. Pat. No. 4,983,316, Starch,
issued Jan. 8, 1991, and U.S. Pat. Nos. 4,639,489 and 4,749.740,
Aizawa et al at column 1, line 46 through column 4, line 35.
The silicone suds suppressor herein preferably comprises
polyethylene glycol and a copolymer of polyethylene
glycol/polypropylene glycol, all having an average molecular weight
of less than about 1,000, preferably between about 100 and 800. The
polyethylene glycol and polyethylenelpolypropylene copolymers
herein have a solubility in water at room temperature of more than
about 2 weight %, preferably more than about 5 weight %.
The preferred solvent herein is polyethylene glycol having an
average molecular weight of less than about 1,000, more preferably
between about 100 and 800, most preferably between 200 and 400, and
a copolymer of polyethylene glycol/polypropylene glycol, preferably
PPG 200/PEG 300. Preferred is a weight ratio of between about 1:1
and 1:10, most preferably between 1:3 and 1:6, of polyethylene
glycol:copolymer of polyethylene-polypropylene glycol.
The preferred silicone suds suppressors used herein do not contain
polypropylene glycol, particularly of 4,000 molecular weight. They
also preferably do not contain block copolymers of ethylene oxide
and propylene oxide, like PLURONIC L101.
Other suds suppressors useful herein comprise the secondary
alcohols (e.g., 2-alkyl alkanols) and mixtures of such alcohols
with silicone oils, such as the silicones disclosed in U.S. Pat.
Nos. 4,798,679, 4,075,118 and EP 150,872. The secondary alcohols
include the C.sub.6 -C.sub.16 alkyl alcohols having a C.sub.1
-C.sub.16 chain. A preferred alcohol is 2-butyl octanol, which is
available from Condea under the trademark ISOFOL 12. Mixtures of
secondary alcohols are available under the trademark ISALCHEM 123
from Enichem. Mixed suds suppressors typically comprise mixtures of
alcohol+silicone at a weight ratio of 1:5 to 5:1.
For any detergent compositions to be used in automatic laundry
washing machines, suds should not form to the extent that they
overflow the washing machine. Suds suppressors, when utilized, are
preferably present in a "suds suppressing amount." By "suds
suppressing amount" is meant that the formulator of the composition
can select an amount of this suds controlling agent that will
sufficiently control the suds to result in a low-sudsing laundry
detergent for use in automatic laundry washing machines. The
compositions herein will generally comprise from 0% to about 5% of
suds suppressor. When utilized as suds suppressors, monocarboxylic
fatty acids, and salts therein, will be present typically in
amounts up to about 5%, by weight, of the detergent composition.
Preferably, from about 0.5% to about 3% of fatty monocarboxylate
suds suppressor is utilized. Silicone suds suppressors are
typically utilized in amounts up to about 2.0%, by weight, of the
detergent composition, although higher amounts may be used. This
upper limit is practical in nature, due primarily to concern with
keeping costs minimized and effectiveness of lower amounts for
effectively controlling sudsing. Preferably from about 0.01% to
about 1% of silicone suds suppressor is used, more preferably from
about 0.25% to about 0.5%. As used herein, these weight percentage
values include any silica that may be utilized in combination with
polyorganosiloxane, as well as any adjunct materials that may be
utilized. Monostearyl phosphate suds suppressors are generally
utilized in amounts ranging from about 0.1% to about 2%, by weight,
of the composition. Hydrocarbon suds suppressors are typically
utilized in amounts ranging from about 0.01% to about 5.0%,
although higher levels can be used. The alcohol suds suppressors
are typically used at 0.2%-3% by weight of the finished
compositions.
In addition to the foregoing ingredients, the compositions herein
can also be used with a variety of other adjunct ingredients which
provide still other benefits in various compositions within the
scope of this invention. The following illustrates a variety of
such adjunct ingredients, but is not intended to be limiting
therein.
Fabric Softeners--Various through-the-wash fabric softeners,
especially the impalpable smectite clays of U.S. Pat. No.
4,062,647, Storm and Nirschl, issued Dec. 13, 1977, as well as
other softener clays known in the art, can optionally be used
typically at levels of from about 0.5% to about 10% by weight in
the present compositions to provide fabric softener benefits
concurrently with fabric cleaning. Clay softeners can be used in
combination with amine and cationic softeners, as disclosed, for
example, in U.S. Pat. No. 4,375,416, Crisp et al, Mar. 1, 1983 and
U.S. Pat. No. 4,291,071, Harris et al, issued Sep. 22, 1981.
Mixtures of cellulase enzymes (e.g., CAREZYME, Novo) and clays are
also useful as high-performance fabric softeners. Various cationic
materials can be added to enhance static control.
Other Ingredients--A wide variety of other ingredients useful in
detergent compositions can be included in the compositions herein,
including other active ingredients, carriers, processing aids, dyes
or pigments, etc. If high sudsing is desired, suds boosters such as
the C.sub.10 -C.sub.16 alkanolamides can be incorporated into the
compositions, typically at 1%-10% levels. The C.sub.10 -C.sub.14
monoethanol and diethanol amides illustrate a typical class of such
suds boosters. Use of such suds boosters with high sudsing adjunct
surfactants such as the amine oxides, betaines and sultaines noted
above is also advantageous. If desired, soluble magnesium salts
such as MgCl.sub.2, MgSO.sub.4, and the like, can be added at
levels of, typically, 0.1%-2%, to provide additional sudsing and/or
product stability, as noted hereinafter.
Various detersive ingredients employed in the present compositions
optionally can be further stabilized by absorbing said ingredients
onto a porous hydrophobic substrate, then coating said substrate
with a hydrophobic coating. Preferably, the detersive ingredient is
admixed with a surfactant before being absorbed into the porous
substrate. In use, the detersive ingredient is released from the
substrate into the aqueous washing liquor, where it performs its
intended detersive function.
To illustrate this technique in more detail, a porous hydrophobic
silica (trademark SIPERNAT D10, DeGussa) is admixed with a
proteolytic enzyme solution containing 3%-5% of C.sub.13-15
ethoxylated alcohol EO(7) nonionic surfactant. Typically, the
enzyme/surfactant solution is 2.5 .times. the weight of silica. The
resulting powder is dispersed with stirring in silicone oil
(various silicone oil viscosities in the range of 500-12,500 can be
used). The resulting silicone oil dispersion is emulsified or
otherwise added to the final detergent matrix. By this means,
ingredients such as the aforementioned enzymes, bleaches, bleach
activators, bleach catalysts, photoactivators, dyes, fluorescers,
fabric conditioners and hydrolyzable surfactants can be "protected"
for use in detergents, including liquid laundry detergent
compositions.
Manufacturing Equipment
As disclosed hereinabbve, the granular compositions of this
invention are conveniently and preferably prepared using three
types of particles, designated (a), (b) and (c) for convenience.
The following illustrates the manufacture of such preferred
compositions. However, it is to be appreciated that other means of
combining the detersive ingredients may be employed without
departing from the spirit and scope of the invention.
Various means and equipment are available to prepare particle (a)
for use in granular detergent compositions according to the present
invention. (Particles [b] and [c] can be prepared by conventional
grinding or agglomerating processes.) Current commercial practice
in the field involves mixing the various ingredients in an aqueous
medium (the so-called "crutcher mix") followed by passage through a
heated spray-drying tower to produce granular particles, such as
(a), which often have a density less than about 550 g/l. If such
low density particles are desired, spray-drying is an acceptable
means for their preparation. If high density particles (above 550
g/l, preferably 650-900 g/l) are desired, and if spray-drying is
used as part of the overall process herein, the resulting
spray-dried particles can be further densified such as by using the
means and equipment described hereinafter. In the alternative, the
formulator can eliminate spray-drying by using mixing, densifying
and granulating equipment that is commercially available. The
following is a nonlimiting description of such equipment suitable
for use herein.
High speed mixer/densifiers can be used in the present process to
prepare high density particles. For example, the device marketed
under the trademark "Lodige CB30" Recycler comprises a static
cylindrical mixing drum having a central rotating shaft with
mixing/cutting blades mounted thereon. In use, the ingredients for
the overall detergent composition are introduced into the drum and
the shaft/blade assembly is rotated at speeds in the range of
100-2500 rpm to provide thorough mixing/densification. Other such
apparatus includes the devices marketed under the trademark "Shugi
Granulator" and under the trademark "Drais K-TTP 80).
Depending on the degree of densification and/or agglomeration
desired, a processing step involving further densification can be
conducted. Equipment such as that marketed under the trademark
"Lodige KM600 Mixer", also known as the "Lodige Ploughshare" can be
used. Such equipment is typically operated at 40-160 rpm. Other
useful equipment includes the device which is available under the
trademark "Drais K-T 160". The Lodige CB or KM type equipment can
be used by itself or sequentially, e.g., by using the CB for paste
dispersion and the KM for agglomeration. Batch or continuous feed
can be employed.
In yet another mode, particle (a) of this invention can be prepared
using a fluidized bed mixer. In this method, the various
ingredients are combined in an aqueous slurry and sprayed into a
fluidized bed of particles comprising, for example, particles of a
zeolite or layered silicate or carbonate builder to provide the
particles (a). In an alternate mode, the slurry can be sprayed into
a fluidized bed of zeolite or layered silicate particles, plus
particles of a surfactant. In such a process, the first step may
optionally include mixing of the slurry using a "Lodige CB30" or
"Flexomix 160", available from Shugi. Fluidized bed or moving beds
of the type available under the trademark "Escher Wyss can be used
in such processes. Other types of granules manufacturing apparatus
useful herein include the apparatus disclosed in U.S. Pat. No.
2,306,898, to G. L. Heller, Dec. 29, 1942.
Whatever the method employed, particles (a) are combined with
percarbonate particles (b) and sulfate particles (c), conveniently
by dry-blending. Any adjunct agents, perfumes, etc., can be admixed
or sprayed onto the mixture of the three types of particles.
The final density of the particles and compositions herein can be
measured by a variety of simple techniques, which typically involve
dispensing a quantity of the granular material into a container of
known volume, measuring the weight of material and reporting the
density as grams/liter. Methods used herein allow the material to
flow into the measuring container under gravity, and without
pressure or other compaction in the measuring container. The
density measurements should be run at room temperature. The
granular material whose density is being measured should be at
least 24 hours old and should be held at room temperature for 24
hours prior to testing. The relative humidity is not particularly
critical, but should not be so high that the particles stick
together. A relative humidity of 50% or less is convenient. Of
course, any clumps in the material should be gently broken up prior
to running the test. In one typical method, the sample of material
is allowed to flow through a funnel mounted on a filling hopper and
stand (#150; Seedburo Equipment Company, Chicago, Ill.) into an
Ohaus cup of known volume and weight (#104; Seedburo). The top of
the cup is positioned about 50 mm from the bottom of the funnel,
and the cup is filled to overflowing. A spatula or other straight
edge is then scraped over the top of the cup, without vibration or
tapping, to level the material, thereby exactly and entirely
filling the cup. The weight of material in the cup is then
measured. Density can be reported as g/l or ounces/cubic inch.
Repeat runs are made and reported as an average. Relative error is
about 0.4%.
The detergent compositions herein will preferably be formulated
such that, during use in aqueous cleaning operations, the wash
water will have a pH of between about 6.5 and about 11, preferably
between about 7.5 and about 10.5. Techniques for controlling pH at
recommended usage levels include the use of buffers, alkalis,
acids, etc., and are well known to those skilled in the art.
The following Examples A and B illustrate granular detergent
compositions according to this invention.
______________________________________ EXAMPLE I Percent* Percent*
Form/Ingredient A B ______________________________________ Spray
-dried granule Zeolite A (1-10 micrometer) 20.50 20.50 Silicate 1.6
R 2.9 -- Silicate 3.2 R -- 2.9 DTPMP 0.3 0.3 Copolymer
maleic/acrylic (mw 70,000) 1.8 1.8 Magnesium sulfate 0.4 0.4 Sodium
sulfate 7.7 8.6 LAS 5.9 0.0 C.sub.16/18 AS 2.5 0.0 45AS 0.0 7.0
13/15AE3S 0.0 0.5 Moisture.sup.1 5.0 5.0 Dry blended Sodium
sulfate** 7.7 7.7 Percarbonate*** 15.0 15.0 TAED 5.0 5.0 Na
carbonate 12.7 12.7 Savinase (4.0 KNPU/g) 0.9 0.9 Spray on
C.sub.14-15 AE.sub.7 5.0 0.0 C.sub.12-15 AE.sub.3 0.0 4.0
Balance/moisture/misc. 100.0 100.0
______________________________________ *Percent by weight of final
composition. .sup.1 Corresponds to 10.6% moisture in the spraydried
granule component said component constituting 47% of the final
composition. **Percarbonate coated with 2.5% of a carbonate/sulfate
mixture (2.5:1 weight ratio) having an activity of 13.25% (AvOx
content), an average particle size of 600 um. ***Na sulfate with 3
ppm iron, 1 ppm copper, 1% particles less than 250 um, 10%
particles less than 425 um, 60% particles less than 600 um, 70%
particles below 850 um, 90% particles less than 1000 um.
The oxidation-sensitive ingredient, such as the brightener, can be
added to the product at any desired level in any convenient manner,
such as by incorporation into the spray-dry mixture, by addition to
the product as a powder, or by spraying onto the product alone
(e.g., the perfume) or in a nonionic ethoxylated (AE) surfactant.
With respect to brightener stability, the measurement of brightener
discoloration can be conducted by visual observation of the stored,
white granules (a distinct yellow color develops) or more
quantitatively by standard photometric means, e.g., Hunter
Whiteness. As can be seen from the following Results, brightener
discoloration towards the yellow is substantially decreased by the
compositions herein. The data show the improved brightener color
stability for granular Composition A of Example I, vs. various test
products using Tinopal DMS brightener (disodium
4,4'-bis[(4-anilino-6-morpholino-1,
3,5-triazin-2-yl)amino]stilbene-2,2'disulfonate). The following
Results are obtained with the brightener which is co-spray dried
with zeolite, silicate and surfactants.
______________________________________ Results (Hunter Color
Measurement) Blue/Yellow Index Test Composition (+ve = yellow; -ve
= blue) ______________________________________ Fresh product -4.20
4 weeks' storage/90.degree. F. (32.degree. C.; 80% relative
humidity) closed carton a) Product + percarbonate (includes
crutched -4.09 silicate) b) Commercial granular product (ARIEL)
-0.75 plus percarbonate/no silicate After 4 weeks' 40.degree. C.
closed carton storage c) Fresh product -4.20 d) Product with
percarbonate (includes -3.92 crutched silicate) e) Product with
percarbonate (no crutched +1.67 silicate)
______________________________________
In a modification of the foregoing, the stabilization benefits of
the silicate are further improved by the addition of soluble
magnesium salts such as Mg Cl.sub.2 or Mg SO.sub.4 to the
spray-dried particles (a), conveniently in the crutcher mix. While
not intending to be limited by theory, it is hypothesized that the
Mg/silicate colloids which form in the crutcher would strongly
scavenge heavy metal cations. Magnesium salt:silicate ratios as low
as 0.2:3.0 are effective.
Moisture in the foregoing compositions can be measured by any
conventional means. In a preferred, simple method, moisture is
measured as moisture loss on heating. For example, a 2 gram sample
of particles is loaded onto the weighing pan of a PM400 Mettler
balance fitted with an LP16 infrared heater. The sample is heated
at 160.degree. C. for 20 minutes. The moisture level is displayed
as a function of percent weight loss. The appropriate moisture
level contributes both to storage stability and, importantly, to
the improved dispensing properties of the granules.
The improved dispensing properties which are also afforded by the
foregoing granules can be measured as follows. The detergent
granules are stored for 4 weeks in closed cartons at 90.degree. F.
(32.degree. C.)/80% relative humidity. After storage, 150 g of the
detergent granules are weighed into the main compartment of a
HotPoint washing machine dispenser drawer. The drawer is
preweighed. Water (20.degree. C.) is flushed through the main
compartment drawer at a rate of 2 liters/min. for 2 minutes. The
excess water in the compartment is drained off and the drawer is
reweighed. This experiment is repeated 6 times. The percent residue
left in the drawer is expressed by the following formula. An
acceptable level of residues is below 15%. The formulations
according to this invention pass this test. ##EQU1##
The foregoing compositions also exhibit acceptable stability of the
percarbonate, i.e., typically less than about 15% decomposition, as
measured in a simple storage test (28.degree. C., sealed bottle,
6-weeks' storage).
The foregoing compositions according to this invention also exhibit
excellent enzyme stability on storage, as compared with
nil-silicate compositions under the same storage test
conditions.
The foregoing compositions according to this invention also exhibit
improved stability with respect to chelants, amine-based fabric
softeners and antistatic agents, perfume and oleyl sulfate
surfactant, as compared with nil-silicate compositions under the
same storage test conditions.
While the foregoing Examples illustrate the practice of the
technology herein, it will be appreciated that simple modifications
can be made without departing from the spirit and scope of the
invention.
* * * * *